Time Travel with the Paleomagicians

This entry is written by Debbie Thomas, co-chief scientist of Expedition 378. It comes from her Expedition 378 Odyssey blog, which can be found here.

Hmmm, maybe that’s enough David Bowie for one shift.

Suggested title revision: Application of the Geomagnetic Polarity Time Scale In The Attribution of Numeric Ages to Marine Sediments. Right, let’s run with the original title.

As promised in Act Your Age, here is the eagerly anticipated story of how our heroes Wendy and Wei save the planet:

A movie poster for the 2003 movie, The Core. It shows a shadowed Earth on a black background. The words "The Core"  are laid over the Earth, with the O placed over the center of the Earth and it up in flames. The top of the poster says "Earth has a deadline" and the bottom says "the only way out is in."
I hope you all remember this geomagnetic gem…

Wendy and Wei are experts in the analysis of the magnetic properties of sediments and rock, and they use these analyses to determine the paleomagnetism of the cores back through geologic time. The polarity (direction of magnetic north and magnetic south) of Earth’s magnetic field has reversed periodically throughout geologic time. Decades of measuring these normals and reversals on radiometrically-dated volcanic material have gifted us the Geomagnetic Polarity Time Scale (GPTS; a portion shown below):

A snippet of the geologic time scale showing epochs, ages, and a paleomagnetism column. The time scale goes from 0-15 million years ago. The paleomagnetism column shows different-sized bands of alternating black and white.

In the Paleomag column above, intervals of geologic time characterized by a normal magnetic polarity (i.e., similar to the modern) are indicated by black rectangles, and the reversals are indicated by white. Our Heroes, Wendy and Wei, analyze the magnetic inclination of the split cores and discrete cubes of sample removed from the working halves, using the shipboard magnetometers:

A scientist, Wendy Zhang, sits at a table lined with lab equipment and computer screens. She is turned away from the camera and is sipping coffee out of a small cup. The lab bench is partially obscured by a large, silver cylinder - a magnetometer.
Godspeed, Wendy.
A photo of the superconducting rock magnetometer, or SRM. The SRM is a long metal cylinder with a hole in one end. A section half of core is lined up with the hole on a track. In the background a scientist, Ingrid Hendy, is working at a computer.
Core sections lined up for analysis in the Superconducting Rock Magnetometer. The SRM literally is as cool as it sounds. Ingrid is in the background describing the sediment structures of the next core.

Prior to analysis, our Heroes must perform a series of demagnetization steps in order to remove the magnetism inherited since these materials were buried on the seafloor. This process can be exceedingly complicated and challenging, particularly on a ship that is surrounded by equipment and structures that complicate the magnetism. In fact, most of what our heroes do is so complicated that we mortals often refer to them as Paleomagicians.

If the sediments behave, our Heroes could collect data that looks like this and correlate it directly to the GPTS:

A set of paleomagnetics data. The right side is a line graph of magnetic inclination, with a scale going from -80 to +80. The left side is a column of black and white stripes like what was on the geologic time scale. When the line graph dips into the negative numbers, the paleomagnetism column shows the color black. When the line graph is mostly in the positive, the column shows white.
Sample of data collected during ODP Leg 208. Keep up the good fight, Heroes!

Time will tell if our Heroes prevail in their epic struggle against carbonate and mud….

In case you were wondering, I’ve moved on to some Billy Joel and Broken Social Scene.

On another note – ever try to tell someone something that was just pant-splitting, soda-spitting, hysterically funny at the time, but elicits no response (at best) from your audience in the re-telling? In a special segment titled You Had to Be There, here are a few of those instances that we have shared during Exp. 378. Could you please at least just humor us and smile? 😉

A printed-out picture taped to a red wall. The picture is of a dark grey core with a couple bright white 3D-printed forms set on top. The caption of the picture is "I have no idea what the micro-paleontologists are complaining about..." There is a sticky note attached to the picture that says "Composition: Foram 100%. The core consists of foraminifer (~several centimeters)."
We may have planted a few 3D printed benthic forams in the barren, brown and stinky mudstone. May have.
Two pictures printed out and taped to a wall. The top one is a microscope image of a radiolarian coated in iron pyrite, which appears black on the microscope. A thought bubble has been drawn over the radiolarian that says "I [heart] Iron". The second image is a grey cat with a wide-eyed, surprised looking expression. The caption on the picture says "Seriously?? No wonder we've got no magnetite."
Just a glimpse of what our Heroes must contend with.

Two of the expedition administrators, Debbie Thomas and Laurel Childress, seated on a couch. Debbie is smiling at the camera with her hands in her lap. Laurel is slouched down on the couch with her arms sprawled out to the sides, and appears to be talking to someone off-frame. A fuzzy green plushie, Little Cthulhu, is resting on the couch between the two scientists. A small penguin plushie is resting on Laurel's leg.
This may have been more tired than funny.

Happy Belated New Year, Heroes!

A whiteboard in the core lab. The whiteboard is decorated with several images of rats and red lanterns for Lunar New Year. The phrase "Happy New Year" is written in the following languages: English, Chinese, German, Italian, Korean, Japanese, Green, Maori, Tagalog, Irish, and Spanish.
Beautiful idea, Wendy!

Until the next time,


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